This invention relates to magnetic bubble domain propagation, and more particularly to a crossover circuit for bubbles propagating in different directions.
The magnetic bubble domain technology uses tiny magnetic domains referred to as "bubbles" that can be made to appear, and and disappear, and rapidly move about particular crystalline magnetic materials under the control of magnetic fields. These materials can be formed into thin sheets with the easy axis of magnetization perpendicular to the sheet.
Controlled propagation is achieved by applying perturbations to the perpendicular bias field. The propagation field can be created by a pattern of easily magnetized and demagnetized material such as Permalloy activated by a rotating in-plane field. The bubbles behave like a magnetic dipole whose south pole is attracted to the north pole induced in the permalloy pattern by the in-plane field. The pattern transforms the rotation of the inplane field into a translating attractive pole pattern which guides the bubbles along the desired paths.
It is frequently necessary to propagate these domains to various storage locations requiring bubbles to move in different directions. It is necessary to provide mechanisms to enable crossovers of interconnections between storage locations.
The present invention presents an improved crossover circuit using inclined bars in a manner that permits a less complex geometry and allows the switching of the permalloy elements with greater simplicity. The use of shorter elements shifts the operation of these elements to a higher drive field and brings the operation of the crossover elements more in line with the propagating circuit.